VASCULAR PLANTS OF STRZESZYN ECOLOGICAL SITE IN POZNAŃ

SCIENTIARUM POLONORUMACTA Silv. Colendar. Rat. Ind. Lignar. 7(4) 2008, 79-91 VASCULAR PLANTS OF STRZESZYN ECOLOGICAL SITE IN POZNAŃ Dorota Wrońska-Pilarek Poznań University of Life Sciences Abstract. In comparison with other natural objects situated within the administrative boundaries of the city of Poznań, the Strzeszyn ecological site distinguishes itself by significant floristic values. The flora of this object includes 531 vascular plants deriving from 91 families and 296 genera, of which 20 species can be found on all-country and regional lists of disappearing and threatened plants. The most valuable floristic elements include Dactylorchiza incarnata, Dianthus superbus, Epipactis palustris and Polypodium vulgare. In addition, 12 trees of monumental or near monumental circumference were found to grow here as well as several dozen splendid trees. Key words: vascular plants, flora of Poznań, Strzeszyn Lake INTRODUCTION Floristic values of areas adjacent to the Strzeszyn Lake, formerly called the Psarskie Lake as well as the Bogdanka River valley have been recognised for a long time by the leading botanists living in Wielkopolska. They were promoted, among others, by Adam Wodziczko, Franciszek Krawiec and Jarosław Urbański, so that already in 1936, the then Poznań provincial governor issued a decree according to which villages situated along the Strzeszyn Lake were covered by landscape protection program [Wodziczko et al. 1938]. Also at present, areas situated in the neighbourhood of the Strzeszyn Lake are considered among the most valuable natural areas situated within the confines of the city of Poznań with plant sites and communities close to natural ones [Łukasiewicz 1982]. In 1994, the City Council passed a resolution No. CV/610/94 establishing the Strzeszyn ecological site with the aim:...to protect biotopes of low bogs, wet meadows, xerothermic swards as well as small forest and water biotopes. Majority of scientists who investigated those areas focused on the most interesting species of plants occurring here [Vorverk 1914, Krawiec and Urbański 1930, Michalski 1931, Wodziczko 1932, Wodziczko et al. 1938, Szweminówna 1949, Krawiecowa 1951, Szulczewski 1951, Szafran 1959, Jackowiak 1990, 1993]. Consequently, the material Corresponding author Adres do korespondencji: Dr Dorota Wrońska-Pilarek, Department of Natural Forestry Foundations of Poznań Univeristy of Life Sciences, Wojska Polskiego 71 E, 60-625 Poznań, Poland, e-mail: pilarekd@up.poznan.pl

80 D. Wrońska-Pilarek available today allows only a superficial review of the flora of the examined region with special emphasis on the site documentation of rare and threatened taxons. Going through the collection and files of the Herbarium of the Section of Plant Taxonomy of Adam Mickiewicz University as well as unpublished scientific papers and the Wielkopolska Herbarium, Jackowiak [1993] found data about places of occurrence or herbarium specimens collected in 1920s and 1930s by Krawiec, Paczoski, Urbański, Tumm and Gołąb and in years 1960s and 1970s by śukowski and Latowski. The area of the Strzeszyn ecological site did not have a complete floristic documentation. In 2000, a manuscript [Wrońska-Pilarek et al. 2000] was prepared which contained a full floristic description of the examined object which served as the basis for the preparation of this elaboration. The principal aim of the performed investigations was: to carry out a floristic inventory of the site, to assess its natural value and to prepare an initial assessment of threats and protection recommendations. Due to editorial regulations, this article does not contain a comprehensive list of inventoried vascular plants as well as maps of distribution of rare and threatened species and the most valuable trees and bushes. However, these materials can be found in the manuscript by Wrońska-Pilarek et al. [2000]. STUDY AREA The Strzeszyn ecological site is situated in the north-western part of the city of Poznań, in Poznań commune, in the district of JeŜyce. It is situated in the catchment area of the Strzeszyn Lake, in the north-western (Golęcin) wedge of greenery which extends from the Citadel, through Sołacz, Golęcin, along the Bogdanka River down to the Kiekrz Lake. The boundaries of the object are presented in Figure 1. The examined site covers the area of 114 ha, of which significant part is taken up by waters, primarily, the Strzeszyn Lake (34.9 ha) [Raport... 1995]. Most of the site area, i.e. about 80 ha, is administered by the Board of Municipal Greenery in Poznań. The site forms part of the Strzeszynek Forest Range and covers compartments 48, 49 and 52. The remaining 34 ha belong to the city of Poznań [Raport... 1994]. The area of floristic investigations was enlarged by the inclusion of areas directly adjacent to it, among others, part of the land which belongs to the Poznań Centre of Sport and Recreation (POSiR) and compartment 48r due to their considerable natural value. METHODS Flora inventory was carried out in the period from March to October 2000. The names of the plant species were given after Mirek et al. [2003] and Seneta and Dolatowski [2008]. The flora statistical characterisation was carried out on the basis of publications by Jackowiak [1993] and śukowski et al. [1995]. The list of species of special care comprised: species covered by legal protection [Rozporządzenie... 2004], those found on red lists all-country [Lista roślin... 1992] and Wielkopolska region [śukowski and Jackowiak 1995], as well as those threatened in the area of the city of Poznań [Jackowiak 1992, 1993].

Vascular plants of Strzeszyn ecological site in Poznań 81 Fig. 1. Boundaries and waters of the Strzeszyn ecological site Rys. 1. Granice i wody uŝytku ekologicznego Strzeszyn The total of 15 experimental plots (0.25 ha) was marked off on the area of the examined site with the aim to conduct investigations on the breast height diameter and height stand structure. All trees were qualified for the breast eight diameter analyses. The plots were established in riparian stands and alder swamp forests, in forest cultures situated on oak-hornbeam sites and in forest cultures with Pinus sylvestris i Betula pendula and Larix decidua. Heights of several trees were measured on each experimental plot and their mean age was determined on the basis of the stand description from 1992. The inventory of the thickest trees consisted in strip survey of stands along a 50 m wide transects running from north to south in sub-compartments of the entire object. The trees were assigned to three groups: trees with monumental circumferences [Instrukcja... 1996, Ruciński 1998], trees with circumferences close to monumental (circumferences 10% smaller than those of monumental ones) and splendid trees (regardless of their circumferences but of unusual appearance and other unusual features). The health status of trees was adopted after Kamiński and Czerniak [2000]. Silvarum Colendarum Ratio et Industria Lignaria 7(4) 2008

82 D. Wrońska-Pilarek RESULTS Flora description The total of 531 taxons from 91 families and 296 genera were found to occur in the examined ecological site, including 5 fern species, 4 conifers as well as 522 mono- and dicotyledons. The number of species in individual families ranges from 1 to 58 and the families richest in species comprise: Asteraceae, Poaceae, Rosaceae, Fabaceae, Caryophyllaceae, Cyperaceae, Brassicaceae, Lamiaceae, Scrophulariaceae, Apiaceae and Salicaceae. The total of 316 species derives from these 11 families which constitutes 59.5% of all the vascular flora of the examined object. Twenty species were found to derive from only 7 families. Generally speaking, families are represented by a small number of species (71 families comprise 1 to 5 species, of which 33 families are represented by only one species). Very rare and rare species were found to be the most numerous group with regard to the number of sites. Dispersed species were found to occur at much smaller proportions. The least numerous species were frequent, very frequent and common species which constitutes only a small percentage of the total flora (Fig. 2). 70.0 Participation, % Udział, % 60.0 50.0 40.0 30.0 20.0 10.0 0.0 I II III IV V VI Class of frequency, % Klasa częstości, % Fig. 2. Percentage participation of species in flora: I very rare, II rare, III dispersed, IV frequent, V very frequent, VI common Rys. 2. Procentowy udział gatunków we florze: I bardzo rzadkie, II rzadkie, III rozproszone, IV częste, V bardzo częste, VI pospolite Plants of indigenous origin (78.3%) were found dominant in the analysed flora and were represented by the total of 416 species, including 159 spontaneophytes and 257 apophytes, while foreign species constitute 21.7%, i.e. 115 taxons, of the flora including 53 kenophytes, 50 archeophytes and 12 ephemerophytes. From among life forms, the most numerous ones were hemicryptophytes (212 species) with terophytes (104), fanerophyes (98) and cryptophytes (92) occurring less frequently and chamephytes (25 species) being the least frequent (Fig. 3).

Vascular plants of Strzeszyn ecological site in Poznań 83 The species found growing in the site belong to 18 sociological-ecological groups. The proportion of species from individual groups ranged from 2 to 75 (1 to 14%). Majority of them is associated with 8 sociological-ecological groups whose proportions exceed 5% (27- -75 species). The remaining 10 groups are represented by 2 to 26 species. The most numerous species on the floristic list of the examined area are those of fertile broad-leaved forests and bush communities (group 1), forests and coastal scrubs, rush and water communities (group 7) as well as fresh and moderately wet meadows (group 9). There are also many species associated with swampy alders (group 6) as well as wet meadows and herbal communities (group 8). Groups 17 and 11 comprising ruderal weeds and terophytic communities occurring in wet and moist sites were the poorest in species (Fig. 4). Raunkiaer s groups Formy Ŝyciowe T K H Ch F 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 Participation, % Udział, % Fig. 3. Percentage participation of Raunkiaer s groups: F fanerophytes, Ch chamephytes, H hemicryptophytes, K cryptophytes, T terophytes Rys. 3. Udział form Ŝyciowych: F fanerofity, Ch chamefity, H hemikryptofity, K kryptofity, T terofity 80 Participation, % Udział, % 70 60 50 40 30 20 10 0 0 2 4 6 8 10 12 14 16 18 20 Sociological-ecological groups Grupy socjologiczno-ekologiczne Fig. 4. Participation of species in sociological-ecological groups [Jackowiak 1993] Silvarum Colendarum Ratio et Industria Lignaria 7(4) 2008

84 D. Wrońska-Pilarek Rys. 4. Udział gatunków w grupach socjologiczno-ekologicznych [Jackowiak 1993] Special care species Out of 531 taxons of vascular plants, 165 species are found on lists of disappearing and threatened plants, primarily, (163 species) on the list prepared by Jackowiak (1993) for the city of Poznań. There are 15 legally protected plant species in the flora of the site, of which 7 are under strict protection and the remaining 8 are partially protected (Table 1). Majority of them is found in one or several places. Frequent species include: Frangula alnus and Viburnum opulus. One place with Polypodium vulgare considered in our city as a dying species was found in the examined ecological site. There are four places in Poznań where this fern can still be found [Jackowiak 1993]. The last information about the site of this species occurring near the Strzeszyn Lake comes from Vorverk s publication [1914]. Table 1. Legally protected species Tabela 1. Gatunki prawnie chronione No Lp. Species name Nazwa gatunkowa Legally protected species Ochrona gatunkowa Category of threat Kategoria zagroŝenia Polska Wlkp. Poznań Frequency Częstość CH Ch V * V * E V P * 1 Convallaria majalis L. I 2 Dactylorhiza incarnata (L.) Soo I 3 Dactylorhiza majalis (Rchb.) Hunt et. Summerh. II 4 Dianthus superbus L. I 5 Epipactis helleborine (L.) Crantz II 6 Epipactis palustris (L.) Crantz I 7 Frangula alnus Mill. IV 8 Helichrysum arenarium (L.) Moench II 9 Listera ovata L. I 10 Nuphar lutea (L.) Sibth. & SM. I 11 Nymphaea alba L. II 12 Ononis spinosa L. I 13 Polypodium vulgare L. I 14 Ribes nigrum L. I 15 Viburnum opulus L. IV CH strict protection, Ch partially protection, V endangered, * unthreatened, E dying out, P potentially liable to danger, I very rare, II rare, IV frequent.

Vascular plants of Strzeszyn ecological site in Poznań 85 CH ochrona ścisła, Ch ochrona częściowa, V zagroŝone, * niezagroŝone, E bezpośrednio zagro- Ŝone, P potencjalnie zagroŝone, I bardzo rzadki, II rzadki, IV częsty. Species rare (category R) in Wielkopolska include: Acer campestre, Cladium mariscus, Crataegus rhipidophylla and Populus nigra, whereas Eriophorum latifolium is treated as a threatened (category V) species in this region. From among the threatened category, potentially threatened P (63%) and threatened V (26%) species are represented most numerously, whereas dying E (5%), potentially threatened (PR) and extinct Ex (2% each) as well as of uncertain threat I and unthreatened N (1% each) constitute a much smaller proportion. Dendroflora Woody plants comprise 98 species making up 18.5% of the entire flora of the examined object and include 48 tree species, 46 bushes and 4 species which can assume either of these forms. Fragments of stands with the species composition resembling most the natural composition are preserved, primarily, in a narrow strip along the Strzeszyn Lake coast. The most frequent trees there are broad-leaved trees associated with riparian communities and alder swamp forests. Majority of the stands growing in the examined site were planted on former farmland and their species composition, to a considerable extent was influenced by man and is strongly distorted. Two pioneering species: Pinus sylvestris and Betula pendula were introduced in regions with poor site conditions. The most numerous species are connected with riparian land, alder swamp and oakhornbeam forests which cover a considerable part of the ecological site. They include, among others: Alnus glutinosa, Prunus padus, Sambucus nigra, Frangula alnus, Viburnum opulus, Acer pseudoplatanus, Quercus robur, Carpinus betulus, Tilia cordata and Acer campestre. Bushes found on the examined area usually grow in communities of mesophilic brushwood which most frequently are made up of: Sambucus nigra, Prunus serotina, Frangula alnus, Viburnum opulus, Corylus avellana, Crataegus monogyna, C. rhipidophylla, Lonicera xylosteum, Rhamnus catharticus, Euonymus europaeus, Cornus sanquinea, and less frequently of Rosa canina and R. dumalis, Rubus plicatus, Prunus spinosa and others. Bushes as well as short trees also occur in osier brushwood with Salix cinerea, S. aurita and S. pentandra as their characteristic species. Among woody plants, common, very frequent and frequent species are relatively rare and their total proportion is about 21.4%. Very rare and rare taxons are dominant and make up 78.6%. Alien woody plants make up a relatively high proportion (reaching 43.9%), whereas indigenous trees and bushes constitute 56.1%. The most popular alien species is the expansive Prunus serotina but Cornus sericea, Quercus rubra and Larix decidua, which does not occur in Wielkopolska naturally, is also fairly numerous. Very intensive penetration of the examined area by tourists causes that there are many dragged species here, primarily, fugitives from gardens and parks. This group is represented, among others, by: Aesculus hippocastanum, Acer pseudoplatanus Purpurascens, Ailanthus altissima, Amorpha fruticosa, Caragana arborescens, Cornus Silvarum Colendarum Ratio et Industria Lignaria 7(4) 2008

86 D. Wrońska-Pilarek sericea, Fagus sylvatica f. purpurea, Juglans regia, Malus domestica, or Syringa vulgaris. The above-mentioned species usually grow singly or in small groups and, therefore, do not exert a significant influence on the character of dendroflora. In all, 544 trees were qualified to the analysis of the breast height diameter structure. Tree breast height diameters were found quite varied ranging from 9 cm to 111 cm (Fig. 5). Breast height diameters of 303 trees were allocated to classes from 9 to 23 cm, 168 trees were 23 to 43 cm thick and the thickness of the remaining 73 trees exceeded 43 cm. Low frequency was observed among the thickest trees which ranged from 1 to 7 specimens. The exception was the tree thickness class from 85 to 87 cm in which 22 trees were found. 70 60 Number of trees Liczba drzew 50 40 30 20 10 0 10 14 18 22 26 30 34 38 42 46 50 54 58 62 66 70 74 78 82 86 90 94 98 102 106 110 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100 104 108 Breast height classes, cm Środki klas grubości, cm Fig. 5. The breast height structure of the trees defined on the basis of 15 trial areas Rys. 5. Struktura pierśnic drzew przedstawiona na podstawie 15 powierzchni próbnych The mean age of stands ranged from 50 to 55 years [Opis... 1992]. The youngest stands are a dozen years old, whereas the oldest ones with Pinus sylvestris are about 120 years old. The majority of stands in the examined site are 41 to 60 years of age (third age class) but stands of the second age class (20-40 years old) are also fairly frequent. Stands over 80 years of age are rare. The youngest, several-year old trees grow on plantations established in the south-western and western parts of the site. The height of 76 trees was measured. The obtained results are very close to the data contained in the stand description from 1992. The mean height of measured trees was approximately 19 m with the smallest trees measuring 5-6 m and the tallest 27 m. The most frequent heights of the trees growing on the examined ecological site ranged from 16 to 22 m. Twelve trees with monumental or close to monumental circumferences were found (Table 2). Apart from the above-mentioned trees, there are 4 more specimens of trees

Vascular plants of Strzeszyn ecological site in Poznań 87 with monumental circumferences Aesculus hippocastanum (400 cm), Betula pendula (238 cm), and two trees Populus canadensis (446, 430 cm), but unfortunately, because of their poor health condition, they cannot be shortlisted as monuments of nature. These trees require urgent sanitary treatment and care. Table 2. The most valuable trees Tabela 2. Najcenniejsze drzewa No Lp. Species name Nazwa gatunkowa Circumference Obwód cm 1 Alnus glutinosa 203* 5 2 Alnus glutinosa 190 5 3 Alnus glutinosa 242* 5 4 Alnus glutinosa 200* 5 5 Alnus glutinosa 225* 4 6 Alnus glutinosa 202* 4 7 Populus nigra 409* 5 8 Prunus serotina 148* 5 9 Pyrus communis 221 5 10 Quercus robur 292 5 11 Tilia cordata 277 5 12 Tilia cordata 343* 5 Bold fonts trees proposed as nature monuments. *Trees of monumental circumference. Pogrubienie drzewa proponowane do objęcia ochroną w formie pomnika przyrody. *Drzewa o obwodzie pomnikowym. Health condition s Stan zdrowotny Several young, splendid trees were found in the examined site which did not reach monumental circumferences yet, but which deserve fully appropriate protection because of their interesting form and very good health condition. This group of trees includes, among others: Carpinus betulus (146, 177 cm) and Fagus sylvatica (152 cm), several Tilia platyphyllos trees or several Populus alba trees (the thickest of them with 347 cm circumference and five others over 250 cm). A plot situated in the compartment 48r with its beautiful specimens of Rhamnus catharticus and Crataegus monogyna deserves particular attention and protection. RECAPITULATION In comparison with other natural objects situated within the confines of the city of Poznań, the Strzeszyn ecological site distinguishes itself by its floristic value as evi- Silvarum Colendarum Ratio et Industria Lignaria 7(4) 2008

88 D. Wrońska-Pilarek denced not only by the number of the described species but also by a significant proportion of legally protected plants as well as plants mentioned on all-country and regional lists of rare and threatened species. The diversified and rich flora of this object comprises 531 taxons of vascular plants which constitutes almost half of all vascular plants from the entire area of the city of Poznań mentioned by Jackowiak [1993]. The fragments of the examined site closest to natural and, hence, floristically most valuable are areas along the coastline of the Strzeszyn Lake of the Fraxino-Alnetum W. Mat (1952) and Ribeso nigri-alnetum Sol.-Górn. (1975) 1987, as well as molinia meadows extending along the Bogdanka River in the north-eastern part of the ecological site. The site conditions found there provide optimal circumstances for the development of many valuable plant species. Twenty species of plants found on all-country and regional lists of disappearing and threatened plants occur on the examined area. Even though in the scale of the entire country or region, populations of the majority of them are not threatened, nevertheless their sites within the boundaries of the city are rather rare. The following species belong to the most valuable elements of the flora of the examined ecological site: Dactylorchiza incarnata, Dianthus superbus, Epipactis palustris and Polypodium vulgare. Although the object situated within the confines of the city is heavily frequented by its inhabitants and is, therefore, under strong anthropo-pressure, its flora has so far managed to withstand human interference as confirmed by its species composition dominated by indigenous plant species. Obviously, this does not mean to say that natural floristic systems survived completely unaffected. Among domestic plant species, anthropophytes are nearly twice as numerous as spontaneophytes. A significant proportion of taxons of alien origin is also worrying of which two neophytes Prunus seronina and Impatiens parviflora are the most dangerous. Man s negative impact is particularly conspicuous in the case of dendroflora. Numbers of tree and bush species of alien origin are nearly the same as those of indigenous species. PROTECTION RECOMMENDATIONS Prohibition of plant destruction and picking. Ban on the introduction of alien plant species. Appropriate formation of stand structure by the introduction into their composition of only indigenous species adapted to the site conditions prevailing on the area of the discussed ecological site. No species of alien origin should be introduced into cultivations (Larix deciduas, L. eurolepis, Fagus sylvatica or Quercus rubra). Whenever possible, gradual removal of trees and bushes of alien origin and their replacement by domestic species. Encouragement of tree and bush species of mesophilic scrub forming the natural forest Bondary. Leaving dead trees in the forest as they provide living environment for many plants and animals. Protection of water and rushes associated with the Strzeszyn Lake and neighbouring ponds (especially Cladium mariscus, Utricularia vulgaris, Nuphar lutea and Nymphea alba). For this reason, it would be advisable to consider limiting the penetration of the

Vascular plants of Strzeszyn ecological site in Poznań 89 coasts of water reservoirs by anglers who pollute lakesides and trample the vegetation destroying or impairing plants. Undertaking steps aiming at the preservation and protection of populations of rare and disappearing plant species. This can be achieved by: protection of communities in which the described species occur; periodical control of the condition of their population; introduction of the rarest species onto areas neighbouring with the ecological site; transfer of individual specimens to botanical or dendrological gardens where they could be reproduced and later on reintroduced into the ecological site. Encouragement of the populations of rare and disappearing plant species by appropriate maintenance of water relations typical for riparian lands, alder swamp forests and wet meadows (primarily molinia meadows) which provide sanctuary for these plants. If these populations are to be maintained and developed, then these meadows cannot be allowed to dry and should be cut periodically. Appropriate protection of sites and regular control of the condition of particularly valuable species which are represented on the examined area in one or two places and are equally rare in Poznań and in the region. This refers, in particular, to Polypodium vulgare, Epipactis palustris or Dianthus superbus. In the case of these species, their introduction into the neighbouring areas can be considered. Protection of selected, most valuable trees of monumental character and splendid specimens. All necessary nursing and sanitary treatments should be carried out on these trees. Acknowledgement I would like to thank Mr Władysław Danielewicz, Ph.D., eng. (Poznań University of Life Sciences) for his help and valuable advice both in the course of field studies and editorial work. REFERENCES Instrukcja sporządzania programu ochrony przyrody w nadleśnictwie [Instruction for the elaboration of a nature conservation project in a forest district]. 1996. Depart. Leśn. Min. Ochr. Środ. Zas. Natur. Leśn. Warszawa [in Polish]. Jackowiak B., 1990. Antropogeniczne przemiany flory roślin naczyniowych Poznania [Floral anthropogenic changes of vascular plants in Poznań]. Wyd. Nauk. UAM Poznań [in Polish]. Jackowiak B., 1992. Rozmieszczenie roślin naczyniowych na terenie miasta Poznania. Gatunki wymarłe [Distribution of vascular plants in Poznań. Extinct species]. Bad. Fizjogr. Pol. Zach. Ser. B, 5-39 [in Polish]. Jackowiak B., 1993. Atlas rozmieszczenia roślin naczyniowych w Poznaniu [Atlas of distribution of vascular plants in Poznań]. Pr. Zakł. Takson. Rośl. UAM Pozn. 2 [in Polish]. Kamiński B., Czerniak A., 2000. Badanie drzewostanów oraz sporządzenie opinii naukowej kwalifikującej do stworzenia wykazu inwentaryzacyjnego starych, cennych drzew na terenie miasta Poznania [Investigations of stands and the preparation of a scientific opinion qualifying the establishment of the inventory list of old, valuable trees found in the city of Poznań]. Kat. InŜ. Leśn. AR Poznań [typescript; in Polish]. Krawiec F., Urbanski J., 1930. Rezultaty wycieczek florystycznych po Wielkopolsce [Results of floristic excursions in Wielkopolska]. Ibidem 1, 52-56 [in Polish]. Silvarum Colendarum Ratio et Industria Lignaria 7(4) 2008

90 D. Wrońska-Pilarek Krawiecowa A., 1951. Analiza geograficzna flory synantropijnej miasta Poznania [Geographical analysis of synanthropic flora of the City of Poznań]. Pr. Kom. Biol. PTPN 13, 1 [in Polish]. Łukasiewicz A., 1982. Kryteria prawidłowego rozwoju terenów zieleni w aglomeracjach miejskich na przykładzie miasta Poznania [Criteria of correct development of green areas in urban agglomerations as exemplified by the City of Poznań]. Wyd. Nauk UAM. Poznań [in Polish]. Michalski K., 1931. Roślinność Jeziora Strzeszyńskiego (szkic fizjograficzny) [Vegetation of the Strzeszyn Lake (physiographic sketch)]. UAM Poznań [typescript; in Polish]. Mirek Z., Piękoś-Mirkowa H., Zając A., Zając M., 2003. Flowering plants and pteridiophytes of Poland. A checklist. Inst. Bot. W. Szafera PAN Kraków [in Polish]. Opis taksacyjny. Lasy Komunalne Miasta Poznania [Poznań City Communal Forests]. 1992. Obręb ewidencyjny Strzeszyn, Psarskie [in Polish]. Raport o stanie środowiska w województwie poznańskim w roku 1993 [Report on the environmental condition of Poznań Voivodeship for 1993]. 1994. Ed. M. Pułyk. Państ. Insp. Ochr. Środ. Warsz. Woj. Insp. Ochr. Środ. Poznań [in Polish]. Raport o stanie środowiska w województwie poznańskim w roku 1994 [Report on the environmental condition of Poznań Voivodeship for 1994]. 1995. Eds M. Pułyk, E. Tybiszewska. Państ. Insp. Ochr. Środ. Warsz. Woj. Insp. Ochr. Środ. Poznań [in Polish]. Rozporządzenie Ministra Środowiska z dnia 9 lipca 2004 r. w sprawie gatunków dziko występujących roślin objętych ochroną [Regulation of the Minister of Environment from July, 9th 2004 concerning wild-growing plants under protection]. 2004. Dz. U. nr 168, poz. 1764 [in Polish]. Ruciński P., 1998. Motywy i kryteria uznawania tworów przyrody za pomniki [Motifs and criteria for the recognition of natural reations as monuments]. Las Pol. 23, 7-10 [in Polish]. Seneta W., Dolatowski J., 2008. Dendrologia [Dendrology]. Wyd. Nauk. PWN Warszawa [in Polish]. Szafran H., 1959. Miasto Poznań i okolica [The City of Poznań and its surroundings]. PTPN Poznań [in Polish]. Szulczewski J.W., 1951. Wykaz roślin naczyniowych w Wielkopolsce dotąd stwierdzonych [List of vascular plants identified in Wielkopolska so far]. Pr. Kom. Biol. PTPN 12 (6), 1-128 [in Polish]. Szweminówna K., 1949. Roślinność Golęcińskiego Klina Zieleni [Vegetation of the Golęcin Green Wedge]. UAM Poznań [typescript; in Polish]. Vorverk. Beitrag zur Flora der Provinz Posen. 1914. Das Ketscher Seengebiet. Zeitschr. Naturwiss. Abteil. Deutsche Gesell. Kunst Wissen. 70/21 (1), 15-17. Wodziczko A., 1932. Dolina Bogdanki w rozbudowie Poznania [The Bogdanka River valley in developing Poznań]. Wyd. Okr. Kom. Ochr. Przyr. Wlkp. Pom. Poznań [in Polish]. Wodziczko A., Krawiec F., Urbański J., 1938. Pomniki i zabytki przyrody Wielkopolski [Monuments and nature monuments of Wielkopolska]. Wyd. Okr. Kom. Ochr. Przyr. Wlkp. Pom. Poznań [in Polish]. Wrońska-Pilarek D., Danielewicz W., Gałązka S., Mizera T., Maciorowski G., 2000. Badania florystyczno-faunistyczne oraz ocena naukowa walorów przyrodniczych uŝytku ekologicznego Strzeszyn [Floristic-faunistic investigations and scientific assessment of natural values of the Strzeszyn ecological site. Department of Environmental Protection of the Municipal Office of Poznań]. Wydz. Ochr. Środ. Urz. M. Pozn. Poznań [typescript; in Polish]. Lista roślin zagroŝonych w Polsce [List of threatened plant species in Poland]. 1992. Eds K. Zarzycki, W. Wojewoda, Z. Heinrich. Inst. Bot. W. Szafera PAN Kraków [in Polish]. śukowski W., Jackowiak B., 1995. Ginące i zagroŝone rośliny naczyniowe Pomorza Zachodniego i Wielkopolski [Endangered and threatened vascular plants of Western Pomerania and Wielkopolska]. Bogucki Wyd. Nauk. Poznań [in Polish]. śukowski W., Latowski K., Jackowiak B., Chmiel J., 1995. Rośliny naczyniowe Wielkopolskiego Parku Narodowego [The vascular plants of Wielkopolski National Park]. Bogucki Wyd. Nauk. Poznań [in Polish].

Vascular plants of Strzeszyn ecological site in Poznań 91 ROŚLINY NACZYNIOWE UśYTKU EKOLOGICZNEGO STRZESZYN W POZNANIU Streszczenie. Na tle innych obiektów przyrodniczych połoŝonych w granicach Poznania, uŝytek ekologiczny Strzeszyn wyróŝnia się znacznymi walorami florystycznymi. Flora obiektu liczy 531 taksonów roślin naczyniowych z 91 rodzin i 296 rodzajów, w tym 20 gatunków umieszczonych na krajowych i regionalnych listach roślin ginących i zagroŝonych. Do najcenniejszych elementów flory uŝytku naleŝą Dactylorchiza incarnata, Dianthus superbus, Epipactis palustris i Polypodium vulgare. Rośnie tu 12 drzew o obwodach pomnikowych lub zbliŝonych do pomnikowych i kilkanaście drzew okazałych. Słowa kluczowe: rośliny naczyniowe, flora Poznania, Jezioro Strzeszyńskie Accepted for print Zaakceptowano do druku: 4.11.2008 For citation Do cytowania: Wrońska-Pilarek D., 2008. Vascular plants of Strzeszyn ecological site in Poznań., Silv. Colendar. Rat. Ind. Lignar. 7(4), 79-91. Silvarum Colendarum Ratio et Industria Lignaria 7(4) 2008